CCAAT/enhancer binding protein α predicts poorer prognosis and prevents energy starvation-induced cell death in hepatocellular carcinoma

<p>CCAAT enhancer binding protein α (C/EBPα) plays an essential role in cellular differentiation, growth, and energy metabolism. Here, we investigate the correlation between C/EBPα and hepatocellular carcinoma (HCC) patient outcomes and how C/EBPα protects cells against energy starvation. Expression of C/EBPα protein was increased in the majority of HCCs examined (191 pairs) compared with adjacent nontumor liver tissues in HCC tissue microarrays. Its upregulation was correlated significantly with poorer overall patient survival in both Kaplan-Meier survival (P = 0.017) and multivariate Cox regression (P = 0.028) analyses. Stable C/EBPα-silenced cells failed to establish xenograft tumors in nude mice due to extensive necrosis, consistent with increased necrosis in human C/EBPα-deficient HCC nodules. Expression of C/EBPα protected HCC cells in vitro from glucose and glutamine starvation-induced cell death through autophagy-involved lipid catabolism. Firstly, C/EBPα promoted lipid catabolism during starvation, while inhibition of fatty acid beta-oxidation significantly sensitized cell death. Secondly, autophagy was activated in C/EBPα-expressing cells, and the inhibition of autophagy by ATG7 knockdown or chloroquine treatment attenuated lipid catabolism and subsequently sensitized cell death. Finally, we identified TMEM166 as a key player in C/EBPα-mediated autophagy induction and protection against starvation.</p><p>CONCLUSION: The C/EBPα gene is important in that it links HCC carcinogenesis to autophagy-mediated lipid metabolism and resistance to energy starvation; its expression in HCC predicts poorer patient prognosis.</p>

Epidermal Growth Factor Removal or Tyrphostin AG1478 Treatment Reduces Goblet Cells &amp; Mucus Secretion of Epithelial Cells from Asthmatic Children Using the Air-Liquid Interface Model

<p>RATIONALE: Epithelial remodelling in asthma is characterised by goblet cell hyperplasia and mucus hypersecretion for which no therapies exist. Differentiated bronchial air-liquid interface cultures from asthmatic children display high goblet cell numbers. Epidermal growth factor and its receptor have been implicated in goblet cell hyperplasia.</p><p>OBJECTIVES: We hypothesised that EGF removal or tyrphostin AG1478 treatment of differentiating air-liquid interface cultures from asthmatic children would result in a reduction of epithelial goblet cells and mucus secretion.</p><p>METHODS: In Aim 1 primary bronchial epithelial cells from non-asthmatic (n = 5) and asthmatic (n = 5) children were differentiated under EGF-positive (10ng/ml EGF) and EGF-negative culture conditions for 28 days. In Aim 2, cultures from a further group of asthmatic children (n = 5) were grown under tyrphostin AG1478, a tyrosine kinase inhibitor, conditions. All cultures were analysed for epithelial resistance, markers of differentiation using immunocytochemistry, ELISA for MUC5AC mucin secretion and qPCR for MUC5AC mRNA.</p><p>RESULTS: In cultures from asthmatic children the goblet cell number was reduced in the EGF negative group (p = 0.01). Tyrphostin AG1478 treatment of cultures from asthmatic children had significant reductions in goblet cells at 0.2μg/ml (p = 0.03) and 2μg/ml (p = 0.003) as well as mucus secretion at 2μg/ml (p = 0.04).</p><p>CONCLUSIONS: We have shown in this preliminary study that through EGF removal and tyrphostin AG1478 treatment the goblet cell number and mucus hypersecretion in differentiating air-liquid interface cultures from asthmatic children is significantly reduced. This further highlights the epidermal growth factor receptor as a potential therapeutic target to inhibit goblet cell hyperplasia and mucus hypersecretion in asthma.</p>

Frequency of mutations and polymorphisms in borderline ovarian tumors of known cancer genes.

Borderline ovarian tumors represent an understudied subset of ovarian tumors. Most studies investigating aberrations in borderline tumors have focused on KRAS/BRAF mutations. In this study, we conducted an extensive analysis of mutations and single-nucleotide polymorphisms (SNPs) in borderline ovarian tumors. Using the Sequenom MassArray platform, we investigated 160 mutations/polymorphisms in 33 genes involved in cell signaling, apoptosis, angiogenesis, cell cycle regulation and cellular senescence. Of 52 tumors analyzed, 33 were serous, 18 mucinous and 1 endometrioid. KRAS c.35G&gt;A p.Gly12Asp mutations were detected in eight tumors (six serous and two mucinous), BRAF V600E mutations in two serous tumors, and PIK3CA H1047Y and PIK3CA E542K mutations in a serous and an endometrioid BOT, respectively. CTNNB1 mutation was detected in a serous tumor. Potentially functional polymorphisms were found in vascular endothelial growth factor (VEGF), ABCB1, FGFR2 and PHLPP2. VEGF polymorphisms were the most common and detected at four loci. PHLPP2 polymorphisms were more frequent in mucinous as compared with serous tumors (P=0.04), with allelic imbalance in one case. This study represents the largest and most comprehensive analysis of mutations and functional SNPs in borderline ovarian tumors to date. At least 25% of borderline ovarian tumors harbor somatic mutations associated with potential response to targeted therapeutics.

Endostatin modulates VEGF-mediated barrier dysfunction in the retinal microvascular endothelium

Recent evidence indicates that the anti-angiogenic peptide endostatin may modulate some of the vasomodulatory effects of vascular endothelial growth factor (VEGF) in the retina, including reduction of blood retinal barrier function although it remains uncertain how endostatin promotes endothelial barrier properties. The current study has sought to examine how physiological levels of endostatin alters VEGF-induced inner BRB function using an in vitro model system and evaluation of occludin and ZO-1 regulatory responses. In addition, the ability of exogenous endostatin to regulate VEGF-mediated retinal vascular permeability in vivo was investigated.<br/><br/>Retinal microvascular endothelial cells (RMEC's) were exposed to various concentrations of endostatin. In parallel studies, RMEC monolayers were treated with vascular endothelial growth factor (VEGF165). Vasopermeability of RMEC monolayers and occludin expression were determined.<br/><br/>Blood retinal barrier integrity was quantified in mouse retina using Evans Blue assay following intravitreal delivery of VEGF165, endostatin or a VEGF/endostatin combination.<br/><br/>Endostatin increased the levels of expression of occludin whilst causing no significant change in FITC-dextran flux across the RMEC monolayer. Endostatin reversed the effects of VEGF165-enhanced permeability between microvascular endothelial cells and induced phosphorylation of occludin. Evans Blue leakage from retinas treated with VEGF was 2.0 fold higher than that of contra-lateral untreated eyes (P&lt;0.05) while leakage of eyes from endostatin treated animals was unchanged. When eyes were injected with a combination of VEGF165 and endostatin there was a significant reduction in retinal vasopermeability when compared to VEGF-injected eyes (P&lt;0.05).<br/><br/>We conclude that endostatin can promote integrity of the retinal endothelial barrier, possibly by preventing VEGF-mediated alteration of tight junction integrity. This suggests that endostatin may be of clinical benefit in ocular disorders where significant retinal vasopermeability changes are present.

Advanced glycation end products induce blood-retinal barrier dysfunction in normoglycemic rats

Advanced glycation end products (AGEs) have been implicated in the progressive vascular dysfunction which occurs during diabetic retinopathy. In the current study we have examined the role of these adducts in blood-retinal barrier (BRB) breakdown and investigated expression of the vasopermeabilizing agent vascular endothelial growth factor (VEGF) in the retina. When normoglycemic rats were injected with AGE-modified albumin daily for up to 10 days there was widespread leakage of FITC-dextran and serum albumin from the retinal vasculature when compared to control animals treated with nonmodified albumin. Ultrastructural examination of the vasculature revealed areas of attenuation of the retinal vascular endothelium and increased vesicular organelles only in the AGE-exposed rats. Quantitative RT-PCR and in situ hybridization demonstrated a significant increase in retinal VEGF mRNA expression (P &lt;0.05). These results suggest that AGEs can initiate BRB dysfunction in nondiabetic rats and a concomitant increase in retinal VEGF expression. These findings may have implications for the role of AGEs in the pathogenesis of diabetic retinopathy.

Expression of the VEGF gene family during retinal vaso-obliteration and hypoxia.

Vascular insufficiency and retinal ischaemia precede many proliferative retinopathies and stimulate secretion of vasoactive growth factors. Vascular endothelial growth factor (VEGF) plays a major role and we therefore investigated the other members of the VEGF family: Placental growth factor (PlGF), VEGF-B, -C, and -D, and platelet derived growth factors (PDGF) A and B. Neonatal mice were exposed to hyperoxia for 5 days and then returned to room air (resulting in acute retinal ischaemia). RT-PCR demonstrated that all the members of the VEGF family are expressed in the retina and in situ hybridization (ISH) located their mRNAs primarily in ganglion cells. Similarly to VEGF itself, VEGF-C, PDGF-A, and PDGF-B were upregulated during retinal ischaemia (P &lt; 0.05). Only PlGF gene expression increased during hyperoxia (P &lt; 0.01). The expression pattern of these growth factors suggests a role in the normal retina and during vaso-obliterative and ischaemic phases.

Impaired retinal angiogenesis in diabetes: role of advanced glycation end products and galectin-3

Suppression of angiogenesis during diabetes is a recognized phenomenon but is less appreciated within the context of diabetic retinopathy. The current study has investigated regulation of retinal angiogenesis by diabetic serum and determined if advanced glycation end products (AGEs) could modulate this response, possibly via AGE-receptor interactions. A novel in vitro model of retinal angiogenesis was developed and the ability of diabetic sera to regulate this process was quantified. AGE-modified serum albumin was prepared according to a range of protocols, and these were also analyzed along with neutralization of the AGE receptors galectin-3 and RAGE. Retinal ischemia and neovascularization were also studied in a murine model of oxygen-induced proliferative retinopathy (OIR) in wild-type and galectin-3 knockout mice (gal3(-/-)) after perfusion of preformed AGEs. Serum from nondiabetic patients showed significantly more angiogenic potential than diabetic serum (P &lt;0.0001) and within the diabetic group, poor glycemic control resulted in more AGEs but less angiogenic potential than tight control (P &lt;0.01). AGE-modified albumin caused a dose-dependent inhibition of angiogenesis (P &lt;0.001), and AGE receptor neutralization significantly reversed the AGE-mediated suppression of angiogenesis (P &lt;0.01). AGE-treated wild-type mice showed a significant increase in inner retinal ischemia and a reduction in neovascularization compared with non-AGE controls (P &lt;0.001). However, ablation of galectin-3 abolished the AGE-mediated increase in retinal ischemia and restored the neovascular response to that seen in controls. The data suggest a significant suppression of angiogenesis by the retinal microvasculature during diabetes and implicate AGEs and AGE-receptor interactions in its causation.

VEGF-induced retinal angiogenic signalling is critically dependent on Ca2+ signalling via Ca2+/calmodulin-dependent protein kinase II

<br/><br/>Purpose. The authors conducted an in vitro investigation of the role of Ca2+-dependent signaling in vascular endothelial growth factor (VEGF)-induced angiogenesis in the retina.<br/><br/>Methods. Bovine retinal endothelial cells (BRECs) were stimulated with VEGF in the presence or absence of 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid-acetoxymethyl ester (BAPTA-AM; intracellular Ca2+ chelator), U73122 (phospholipase C (PLC) inhibitor), xestospongin C (Xe-C), and 2-aminoethoxydiphenyl borate (2APB) (inhibitors of inositol-1,4,5 triphosphate (IP3) signaling). Intracellular Ca2+ concentration ([Ca2+]i) was estimated using fura-2 Ca2+ microfluorometry, Akt phosphorylation quantified by Western blot analysis, and angiogenic responses assessed using cell migration, proliferation, tubulogenesis, and sprout formation assays. The effects of the Ca2+/calmodulin-dependent protein kinase II (CaMKII) inhibitor KN93 were also evaluated on VEGF-induced Akt signaling and angiogenic activity.<br/><br/>Results. Stimulation of BRECs with 25 ng/mL VEGF induced a biphasic increase in [Ca2+]i, with an initial transient peak followed by a sustained plateau phase. VEGF-induced [Ca2+]i increases were almost completely abolished by pretreating the cells with BAPTA-AM, U73122, Xe-C, or 2APB. These agents also inhibited VEGF-induced phosphorylation of Akt, cell migration, proliferation, tubulogenesis, and sprouting angiogenesis. KN93 was similarly effective at blocking the VEGF-induced activation of Akt and angiogenic responses.<br/><br/>Conclusions. VEGF increases [Ca2+]i in BRECs through activation of the PLC-IP3 signal transduction pathway. VEGF-induced phosphorylation of the proangiogenic protein Akt is critically dependent on this increase in [Ca2+]i and the subsequent activation of CaMKII. Pharmacologic inhibition of Ca2+-mediated signaling in retinal endothelial cells blocks VEGF-induced angiogenic responses. These results suggest that the PLC/IP3/Ca2+/CaMKII signaling pathway may be a rational target for the treatment of angiogenesis-related disorders of the eye.<br/>

Chemotherapy-Induced Activation of ADAM-17: A Novel Mechanism of Drug Resistance in Colorectal Cancer

Purpose: We have shown previously that exposure to anticancer drugs can trigger the activation of human epidermal receptor survival pathways in colorectal cancer (CRC). In this study, we examined the role of ADAMs (a disintegrin and metalloproteinases) and soluble growth factors in this acute drug resistance mechanism.<br/><br/>Experimental Design: In vitro and in vivo models of CRC were assessed. ADAM-17 activity was measured using a fluorometric assay. Ligand shedding was assessed by ELISA or Western blotting. Apoptosis was assessed by flow cytometry and Western blotting.<br/><br/>Results: Chemotherapy (5-fluorouracil) treatment resulted in acute increases in transforming growth factor-a, amphiregulin, and heregulin ligand shedding in vitro and in vivo that correlated with significantly increased ADAM-17 activity. Small interfering RNA–mediated silencing and pharmacologic inhibition confirmed that ADAM-17 was the principal ADAM involved in this prosurvival response. Furthermore, overexpression of ADAM-17 significantly decreased the effect of chemotherapy on tumor growth and apoptosis. Mechanistically, we found that ADAM-17 not only regulated phosphorylation of human epidermal receptors but also increased the activity of a number of other growth factor receptors, such as insulin-like growth factor-I receptor and vascular endothelial growth factor receptor.<br/><br/>Conclusions: Chemotherapy acutely activates ADAM-17, which results in growth factor shedding, growth factor receptor activation, and drug resistance in CRC tumors. Thus, pharmacologic inhibition of ADAM-17 in conjunction with chemotherapy may have therapeutic potential for the treatment of CRC.

Exudative AMD subtypes and eligibility for treatment with ranibizumab

Purpose To ascertain the proportion of patients with neovascular age-related macular degeneration (AMD) eligible for intravitreal treatment with monoclonal antibodies to vascular endothelial growth factor, on the basis of inclusion criteria used in pivotal clinical trials.

Antibody Targeting of Cathepsin S Inhibits Angiogenesis and Synergistically Enhances Anti-VEGF

<p>BACKGROUND: Angiogenesis is a key hallmark of tumourigenesis and its inhibition is a proven strategy for the development of novel anti-cancer therapeutics. An important aspect of early angiogenesis is the co-ordinated migration and invasion of endothelial cells through the hypoxic tumour tissue. Cathepsin S has been shown to play an important role in angiogenesis as has vascular endothelial growth factor (VEGF). We sought to assess the anti-angiogenic effect of Fsn0503, a novel cathepsin S inhibitory antibody, when combined with anti-VEGF on vascular development.</p><p>METHODOLOGY/PRINCIPAL FINDINGS: Cathepsin S expression and secretion from endothelial cells was characterised using RT-PCR and western blotting. We further show that cathepsin S promotes pericellular hydrolysis of extracellular matrix components in the tumour microenvironment and facilitates endothelial invasion. The cathepsin S inhibitory antibody, Fsn0503, blocks extracellular proteolysis, inhibiting endothelial invasion and tube formation in cell-based assays. The anti-angiogenic effects of Fsn0503 were also shown in vivo where it significantly retarded the development of vasculature in human xenograft models. Furthermore, when Fsn0503 was combined with an anti-VEGF antibody, a synergistic inhibition of microvascular development was observed.</p><p>CONCLUSIONS/SIGNIFICANCE: Taken together, this data demonstrates that the antibody-mediated targeting of cathepsin S represents a novel method of inhibiting angiogenesis. Furthermore, when used in combination with anti-VEGF therapies, Fsn0503 has the potential to significantly enhance current treatments of tumour neovascularisation and may also be of use in the treatment of other conditions associated with inappropriate angiogenesis.</p>

Association of VEGF-1499C -&gt; T polymorphism with diabetic nephropathy in type 1 diabetes mellitus

Vascular endothelial growth factor (VEGF) is reported to be implicated in the development of diabetic nephropathy. We performed a case-control study to determine if VEGF-2578C -&gt; A, VEGF-1499C -&gt; T, and VEGF-635G -&gt; C single-nucleotide polymorphisms (SNPs) in the VEGF gene are associated with predisposition to diabetic nephropathy in type I diabetes. Genomic DNA was obtained from Irish type I diabetic individuals with nephropathy (cases, n=242) and those without nephropathy (controls, n=301), in addition to 400 healthy control samples. These samples were genotyped for the three SNPs using TaqMan or Pyrosequencing technology. Chi-squared analyses revealed no significant differences in genotype or allele frequencies in cases versus controls for VEGF-2578C -&gt; A (genotype, P=.58; allele, P=.52) and VEGF-635G -&gt; C (genotype, P=.58; allele, P=.33). However, a positive association with diabetic nephropathy was observed for the VEGF-1499T allele in the Northern Ireland population (P

Differential expression of steroid 5 alpha-reductase isozymes and association with disease severity and angiogenic genes predict their biological role in prostate cancer

The biological role of steroid 5 alpha-reductase isozymes (encoded by the SRD5A1 and SRD5A2 genes) and angiogenic factors that play important roles in the pathogenesis and vascularization of prostate cancer (PC) is poorly understood. The sub-cellular expression of these isozymes and vascular endothelial growth factor (VEGF) in PC tissue microarrays (n=62) was examined using immunohistochemistry. The effect of SRD5A inhibition on the angiogenesis pathway genes in PC was also examined in prostate cell lines, LNCaP, PC3, and RWPE-1, by treating them with the SRD5A inhibitors finasteride and dutasteride, followed by western blot, quantitative PCR, and ELISA chip array techniques. In PC tissues, nuclear SRD5A1 expression was strongly associated with higher cancer Gleason scores (P=0.02), higher cancer stage (P=0.01), and higher serum prostate specific antigen (PSA) levels (P=0.01), whereas nuclear SRD5A2 expression was correlated with VEGF expression (P=0.01). Prostate tumor cell viability was significantly reduced in dutasteride-treated PC3 and RWPE-1 cells compared with finasteride-treated groups. Expression of the angiogenesis pathway genes transforming growth factor beta 1 (TGFB1), endothelin (EDN1), TGF alpha (TGFA), and VEGFR1 was upregulated in LNCaP cells, and at least 7 out of 21 genes were upregulated in PC3 cells treated with finasteride (25 mu M). Our findings suggest that SRD5A1 expression predominates in advanced PC, and that inhibition of SRD5A1 and SRD5A2 together was more effective in reducing cell numbers than inhibition of SRD5A2 alone. However, these inhibitors did not show any significant difference in prostate cell angiogenic response. Interestingly, some angiogenic genes remained activated after treatment, possibly due to the duration of treatment and tumor resistance to inhibitors. Endocrine-Related Cancer (2010) 17 757-770

Tissue microarrays characterise the clinical significance of a VEGF-A protein expression signature in gastrointestinal stromal tumours

A tissue microarray analysis of 22 proteins in gastrointestinal stromal tumours ( GIST), followed by an unsupervised, hierarchical monothetic cluster statistical analysis of the results, allowed us to detect a vascular endothelial growth factor ( VEGF) protein overexpression signature discriminator of prognosis in GIST, and discover novel VEGF-A DNA variants that may have functional significance.

Deletion of Gremlin1 increases cell proliferation and migration responses in mouse embryonic fibroblasts

Gremlin1 (Grem1) is an antagonist of bone morphogenetic proteins (BMPs) that plays a critical role in embryonic and postnatal development. Grem1 has been implicated as both a promoter and an inhibitor of cell proliferation driven by BMP-4 and other mitogens in a diverse range of cell types. Recent data showed that Grem1 can trigger angiogenesis via vascular endothelial growth factor receptor (VEGFR2) binding, highlighting that the precise modalities of Grem1 signalling require further elucidation.